Lactating dairy cows (n = 72) with a mature corpus luteum (CL) (diameter of >= 17 mm) determined by ultrasonography and having a follicle with a diameter of >= 10 min were randomly assigned to four groups ... [more ▼]

Lactating dairy cows (n = 72) with a mature corpus luteum (CL) (diameter of >= 17 mm) determined by ultrasonography and having a follicle with a diameter of >= 10 min were randomly assigned to four groups. Cows were treated with cloprostenol i.m. once or twice, or with dinoprost i.m. once or twice with an 8-h interval. The ovaries of each cow were scanned daily by transrectal ultrasonography to measure the changes in the areas of CL and the largest follicle and to determine the occurrence of ovulation. Oestrus was verified twice daily. In addition, blood sample was withdrawn from each cow daily for measuring progesterone (P4) concentrations. Significant decreases in the percentage changes relative to areas of CL and P4 concentrations or increases in the percentage changes in the area of the largest follicle on day 0 were detected in each group during the experiment. However, the type of the drug and the number of the treatments had no significant effect on those parameters. Cows ovulated with or without showing oestrus (group A) and cows exhibiting no oestrus and ovulation (group 13) were also evaluated. In contrast to the mean area of the CL and the mean concentration of P4 on day 0, the mean area of the largest follicles between, the two groups on day 0 differed significantly Significant decreases in the percentage changes relative to the area of the CL and P4 concentration or increases in the percentage changes relative to the area of the largest follicle during the experiment were detected in both groups; however, there were no group differences. Treatment of dairy cows with two injections of prostaglandins (cloprostenol or dinoprost) at an 8-h interval resulted in more cows being, observed in oestrus within 5 days after treatment and having significantly higher pregnancy rate than those treated with a single prostaglandin injection. [less ▲]

Lactating dairy cows with a mature corpus luteum (CL) (diameter of greater than or equal to17 mm determined by ultrasonography) and having a follicle with a diameter of 10 mm (n = 49) were randomly ... [more ▼]

Lactating dairy cows with a mature corpus luteum (CL) (diameter of greater than or equal to17 mm determined by ultrasonography) and having a follicle with a diameter of 10 mm (n = 49) were randomly assigned to three groups. The first group was treated with a single dose of exogenous prostaglandin (25 mg), while the second group was treated with 35 mg on day 0, and the third group served as control in order to evaluate the effect of rectal manipulation on the CL during ultrasonographic examination. Blood samples were collected daily for analysing progesterone (P4) concentrations. In group 1 the incidence of oestrus and artificial insemination (AI) in 10 days after treatment was 95% (19 of 20). The conception rate was 31.6%, and the average time to oestrus after treatment was 3.7 day. In group 2 the incidence of oestrus and A.I. was 84.2% (16/19). The conception rate was 31.2%, and the average time to oestrus after treatment was 2.8 day. In the untreated group only two cows (2/10) exhibited oestrus during the examined period and none of them became pregnant. There were no significant differences between the two treated groups in terms of reduction in the area of CL and P4 concentrations and of an increase in the area of the dominant follicles. At the same time, the decrease in the percentage changes relative to the area of CL and to the concentrations of P4 were statistically significant in both treated groups. [less ▲]

In ruminants, pregnancy associated glycoproteins (PAG), synthesized in the outer layers of the trophoblast, enter the maternal bloodstream. In this study, blood samples from cows in the postpartum period ... [more ▼]

In ruminants, pregnancy associated glycoproteins (PAG), synthesized in the outer layers of the trophoblast, enter the maternal bloodstream. In this study, blood samples from cows in the postpartum period, pregnant cows and calves were collected to determine 1) the clearance rate of PAG, 2) the accuracy of PAG measurements used for pregnancy diagnosis and 3) PAG concentrations and clearance rate in newborn calves. A curvilinear decline in PAG was found with increasing days from calving. Between day 70–80 pp 3 out of 11 samples (27%) had PAG concentrations > 4 ng/ml plasma. A cut-off value of 4 ng/ml was found to give the best accuracy for pregnancy diagnosis 28–36 days after service (n ¼58: sensitivity¼0.97; specificity ¼1.0). PAG concentrations in newborn calves (n¼10) varied between 78–880 ng/ml, declining with increasing age in a curvilinear pattern to < 1 ng/ml between 20–40 days pp. In two male twin calves PAG concentrations were 880 and 101 ng/ml, respectively, at one day of age. We conclude: 1) 4 ng PAG /ml provides the best cut-off value for pregnancy diagnosis. 2) Cows serviced before 60 days pp can produce false positive pregnancy diagnoses due to PAG originating from the previous pregnancy. 3) High PAG concentrations can be found in newborn calves. [less ▲]

The aim of the present workwas to compare the efficiency of transrectal ultrasonography technique and the determination of the pregnancy-associated glycoproteins (PAG) concentrations in plasma samples for ... [more ▼]

The aim of the present workwas to compare the efficiency of transrectal ultrasonography technique and the determination of the pregnancy-associated glycoproteins (PAG) concentrations in plasma samples for pregnancy diagnosis in goats. Thirty nine Canary goats were synchronized and naturally mated every 12 hours throughout oestrous. Blood samples were collected on days 17, 18, 19, 20, 22, 24, 26 and 28 and transrectal ultrasonography was carried out on days 20, 22, 24, 26 and 28 (Day 0¼day of the last mating). PAG concentrations were analysed by a RIA method previously validated. There were 23 pregnant goats (10 single and 13 multiple pregnancies) and 16 nonpregnant goats. The pregnancy diagnosis was a little earlier by PAG determination than transrectal ultrasonography (sensitivity: 95 and 91% on Day 24 and 100 and 96% on Day 26, respectively). The ultrasonography allowed to discriminate between single and multiple pregnancies in 70% of goats (16/23) on Day 28 of pregnancy. The PAG concentrations were significantly higher in multiple than single pregnancies from Day 19 onwards, suggesting that it could also be used as a tool to discriminate between single and multiple gestations. (Supported by D.G. de Universidades del Gobierno de Canarias). [less ▲]

Pregnancy-associated glycoproteins (PAGs) constitute a large family of glycoproteins that are synthesized in the superficial layer of the ruminant placenta according to a spatial and temporal expression ... [more ▼]

Pregnancy-associated glycoproteins (PAGs) constitute a large family of glycoproteins that are synthesized in the superficial layer of the ruminant placenta according to a spatial and temporal expression pattern. When PAGs are released in the maternal blood they can be used for pregnancy diagnosis, pregnancy follow-up and for the monitoring of the trophoblastic function. Three different radioimmunoassay systems (RIA 1, RIA 2 and RIA 3) using antisera produced against PAG I67 (RIA 1), PAG55+62 (RIA 2) and PAG55+59 (RIA 3) were used in this investigation in order to measure the PAG concentration in plasma samples withdrawn from pregnant cows and heifers during different periods following artificial insemination (AI). These systems were able to detect PAG molecules in the maternal blood as early as 21 days after AI in different concentrations (RIA 1: 0.43 +/- 0.24 ng/ml, mean +/- SD; RIA 2: 0.48 +/- 0.24 ng/ml; RIA 3: 0.64 +/- 0.37 ng/ml). On days 32 and 42 RIA 2 (4.30 +/- 1.32 ng/ml and 5.56 +/- 1.95 ng/ml) and RIA 3 (4.17 +/- 1.15 ng/ml and 5.60 +/- 1.89 ng/ml) presented significantly (p < 0.0001) higher PAG concentrations than those of RIA 1 (2.43 +/- 0.81 ng/ml and 4.01 +/- 1.48 ng/ml), respectively. After day 21, significant correlations (p < 0.0001; r >/= 0.929) were determined between the three systems. Additionally the three individual PAG profiles presented in this study showed that PAG molecules secreted in the maternal blood between 21 and 50 days after AI were better recognized by the RIA 2 and RIA 3 systems. This study clearly indicated that the ability of a RIA test to recognize PAG molecules in the maternal blood can be improved by carefully selecting the antiserum. [less ▲]

Pregnancy-associated glycoproteins (PAGs) isolated from the placenta of various ruminant species are enzymatically inactive members of the aspartic proteinase family. The measurement of these proteins in ... [more ▼]

Pregnancy-associated glycoproteins (PAGs) isolated from the placenta of various ruminant species are enzymatically inactive members of the aspartic proteinase family. The measurement of these proteins in the maternal blood can be a good indicator of the presence of a live embryo. As certain aspartic proteinases are present in biological fluids in physiological and pathological conditions at various concentrations, it was necessary to determine the specificity of three radioimmunoassay (RIA) systems currently used for the detection of PAG molecules. Commercially available members of the aspartic proteinase family like pepsinogen, pepsin, chymosin, rennet, cathepsin D and renin were tested in a wide concentration range (10 ng/ml - 1 mg/ml). Pepsinogen cross-reacted in RIA 1, RIA 2 and RIA 3 over 1 mg/ml, 50 microg/ml and 500 microg/ml concentrations, respectively. In the presence of pepsin, cross-reaction was observed in RIA 1, RIA 2 and RIA 3 over 1 mg/ml, 500 microg/ml and 1 mg/ml concentrations, respectively. Chymosin and rennet could cross-react in RIA 2 and RIA 3, while renin and cathepsin D did not decrease the binding of the tracer to antisera more, than that of the minimal detection limit. As the plasma/serum concentrations of the examined aspartic proteinases reported in the literature were outside the concentration range where cross-reaction was observed, it can be concluded that these RIA systems were specific for the detection of PAGs in biological fluids. [less ▲]